SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cac3acfb2f0676a4605d4bacdb35416cda002686eb6b8483e64b7a786e0d08e7' 
  AND token = 'MVkIEWzgyEp9efLwNXf3XkbB68394aZxq0DLLNPs+1Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}